212561506505 has 4 divisors (see below), whose sum is σ = 255073807812. Its totient is φ = 170049205200.

The previous prime is 212561506447. The next prime is 212561506517. The reversal of 212561506505 is 505605165212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 35532627001 + 177028879504 = 188501^2 + 420748^2 .

It is not a de Polignac number, because 212561506505 - 2²⁴ = 212544729289 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21256150646 + ... + 21256150655.

It is an arithmetic number, because the mean of its divisors is an integer number (63768451953).

Almost surely, 2^212561506505 is an apocalyptic number.

It is an amenable number.

212561506505 is a deficient number, since it is larger than the sum of its proper divisors (42512301307).

212561506505 is an equidigital number, since it uses as much as digits as its factorization.

212561506505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42512301306.

The product of its (nonzero) digits is 90000, while the sum is 38.

The spelling of 212561506505 in words is "two hundred twelve billion, five hundred sixty-one million, five hundred six thousand, five hundred five".